/*
 * Copyright (C) 2010 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.hi.hiparty.util;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.lang.ref.SoftReference;
import java.lang.ref.WeakReference;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Color;
import android.graphics.drawable.ColorDrawable;
import android.graphics.drawable.Drawable;
import android.net.http.AndroidHttpClient;
import android.os.AsyncTask;
import android.os.Environment;
import android.os.Handler;
import android.util.Log;
import android.widget.ImageView;

/**
 * This helper class download images from the Internet and binds those with the
 * provided ImageView.
 * 
 * <p>
 * It requires the INTERNET permission, which should be added to your
 * application's manifest file.
 * </p>
 * 
 * A local cache of downloaded images is maintained internally to improve
 * performance.
 */
public class ImageDownloader {

	private static final String LOG_TAG = "ImageDownloader";

	public enum Mode {
		NO_ASYNC_TASK, NO_DOWNLOADED_DRAWABLE, CORRECT
	}

	private Mode mode = Mode.CORRECT;

	/**
	 * Download the specified image from the Internet and binds it to the
	 * provided ImageView. The binding is immediate if the image is found in the
	 * cache and will be done asynchronously otherwise. A null bitmap will be
	 * associated to the ImageView if an error occurs.
	 * 
	 * @param url
	 *            The URL of the image to download.
	 * @param imageView
	 *            The ImageView to bind the downloaded image to.
	 */
	public void download(String url, ImageView imageView,
			ImageViewDownloadedCallBack callback,
			Map<String, Object> callbackParams) {
		resetPurgeTimer();
		Bitmap bitmap = getBitmapFromCache(url);
		if (bitmap == null) {
			bitmap = getBitmapFromSDCard(url);
		}

		if (bitmap == null) {
			forceDownload(url, imageView, callback, callbackParams);
		} else {
			cancelPotentialDownload(url, imageView);
			imageView.setImageBitmap(bitmap);
			if(null != callback){
				callback.onImageDownloaded(imageView, bitmap, callbackParams);
			}
		}
	}
	
	public void download(String url, ImageView imageView){
		resetPurgeTimer();
		Bitmap bitmap = getBitmapFromCache(url);
		if (bitmap == null) {
			bitmap = getBitmapFromSDCard(url);
		}

		if (bitmap == null) {
			forceDownload(url, imageView, null, null);
		} else {
			cancelPotentialDownload(url, imageView);
			imageView.setImageBitmap(bitmap);
		}
	}

	/**
	 * Download the specified image from the Internet and binds it to the
	 * provided ImageView. The binding is immediate if the image is found in the
	 * cache and will be done asynchronously otherwise. A null bitmap will be
	 * associated to the ImageView if an error occurs.
	 * 
	 * @param url
	 *            The URL of the image to download.
	 * @param imageView
	 *            The ImageView to bind the downloaded image to.
	 */
	public void download(String url, ImageDownloadedCallBack callback,
			Map<String, Object> callbackParams) {
		resetPurgeTimer();
		Bitmap bitmap = getBitmapFromCache(url);
		if (bitmap == null) {
			bitmap = getBitmapFromSDCard(url);
		}

		if (bitmap == null) {
			BitmapDownloaderTask task = new BitmapDownloaderTask(callback,
					callbackParams);
			task.execute(url);
			return;
		} else {
			callback.onImageDownloaded(bitmap, callbackParams);
			return;
		}
	}

	/*
	 * Same as download but the image is always downloaded and the cache is not
	 * used. Kept private at the moment as its interest is not clear. private
	 * void forceDownload(String url, ImageView view) { forceDownload(url, view,
	 * null); }
	 */

	/**
	 * Same as download but the image is always downloaded and the cache is not
	 * used. Kept private at the moment as its interest is not clear.
	 */
	private void forceDownload(String url, ImageView imageView,
			ImageViewDownloadedCallBack callback,
			Map<String, Object> callbackParams) {
		// State sanity: url is guaranteed to never be null in
		// DownloadedDrawable and cache keys.
		if (url == null) {
			imageView.setImageDrawable(null);
			return;
		}

		if (cancelPotentialDownload(url, imageView)) {
			switch (mode) {
			case NO_ASYNC_TASK:
				Bitmap bitmap = downloadBitmap(url);
				addBitmapToCache(url, bitmap);
				imageView.setImageBitmap(bitmap);
				break;

			case NO_DOWNLOADED_DRAWABLE:
				BitmapDownloaderTaskForImageView task = new BitmapDownloaderTaskForImageView(
						imageView, callback, callbackParams);
				task.execute(url);
				break;

			case CORRECT:
				task = new BitmapDownloaderTaskForImageView(imageView,
						callback, callbackParams);
				DownloadedDrawable downloadedDrawable = new DownloadedDrawable(
						task);
				imageView.setImageDrawable(downloadedDrawable);
				task.execute(url);
				break;
			}
		}
	}

	/**
	 * Returns true if the current download has been canceled or if there was no
	 * download in progress on this image view. Returns false if the download in
	 * progress deals with the same url. The download is not stopped in that
	 * case.
	 */
	private static boolean cancelPotentialDownload(String url,
			ImageView imageView) {
		BitmapDownloaderTaskForImageView bitmapDownloaderTask = getBitmapDownloaderTask(imageView);

		if (bitmapDownloaderTask != null) {
			String bitmapUrl = bitmapDownloaderTask.url;
			if ((bitmapUrl == null) || (!bitmapUrl.equals(url))) {
				bitmapDownloaderTask.cancel(true);
			} else {
				// The same URL is already being downloaded.
				return false;
			}
		}
		return true;
	}

	/**
	 * @param imageView
	 *            Any imageView
	 * @return Retrieve the currently active download task (if any) associated
	 *         with this imageView. null if there is no such task.
	 */
	private static BitmapDownloaderTaskForImageView getBitmapDownloaderTask(
			ImageView imageView) {
		if (imageView != null) {
			Drawable drawable = imageView.getDrawable();
			if (drawable instanceof DownloadedDrawable) {
				DownloadedDrawable downloadedDrawable = (DownloadedDrawable) drawable;
				return downloadedDrawable.getBitmapDownloaderTask();
			}
		}
		return null;
	}

	public Bitmap downloadBitmap(String url) {

		final int IO_BUFFER_SIZE = 4 * 1024;

		// AndroidHttpClient is not allowed to be used from the main thread
		final HttpClient client = (mode == Mode.NO_ASYNC_TASK) ? new DefaultHttpClient()
				: AndroidHttpClient.newInstance("Android");
		final HttpGet getRequest = new HttpGet(url);

		try {
			HttpResponse response = client.execute(getRequest);
			final int statusCode = response.getStatusLine().getStatusCode();
			if (statusCode != HttpStatus.SC_OK) {
				Log.w("ImageDownloader", "Error " + statusCode
						+ " while retrieving bitmap from " + url);
				return null;
			}

			final HttpEntity entity = response.getEntity();
			if (entity != null) {
				InputStream inputStream = null;
				try {
					inputStream = entity.getContent();
					// return BitmapFactory.decodeStream(inputStream);
					// Bug on slow connections, fixed in future release.
					Bitmap bitmap = BitmapFactory
							.decodeStream(new FlushedInputStream(inputStream));

					return bitmap;
				} finally {
					if (inputStream != null) {
						inputStream.close();
					}
					entity.consumeContent();
				}
			}
		} catch (IOException e) {
			getRequest.abort();
			Log.w(LOG_TAG, "I/O error while retrieving bitmap from " + url, e);
		} catch (IllegalStateException e) {
			getRequest.abort();
			Log.w(LOG_TAG, "Incorrect URL: " + url);
		} catch (Exception e) {
			getRequest.abort();
			Log.w(LOG_TAG, "Error while retrieving bitmap from " + url, e);
		} finally {
			if ((client instanceof AndroidHttpClient)) {
				((AndroidHttpClient) client).close();
			}
		}
		return null;
	}

	/*
	 * An InputStream that skips the exact number of bytes provided, unless it
	 * reaches EOF.
	 */
	static class FlushedInputStream extends FilterInputStream {
		public FlushedInputStream(InputStream inputStream) {
			super(inputStream);
		}

		@Override
		public long skip(long n) throws IOException {
			long totalBytesSkipped = 0L;
			while (totalBytesSkipped < n) {
				long bytesSkipped = in.skip(n - totalBytesSkipped);
				if (bytesSkipped == 0L) {
					int b = read();
					if (b < 0) {
						break; // we reached EOF
					} else {
						bytesSkipped = 1; // we read one byte
					}
				}
				totalBytesSkipped += bytesSkipped;
			}
			return totalBytesSkipped;
		}
	}

	/**
	 * The actual AsyncTask that will asynchronously download the image.
	 */
	class BitmapDownloaderTaskForImageView extends
			AsyncTask<Object, Void, Bitmap> {
		private String url;
		private Map<String, Object> callbackParams;
		private final WeakReference<ImageView> imageViewReference;
		private ImageViewDownloadedCallBack imageDownloadedCallBack;

		public BitmapDownloaderTaskForImageView(ImageView imageView) {
			imageViewReference = new WeakReference<ImageView>(imageView);
		}

		public BitmapDownloaderTaskForImageView(ImageView imageView,
				ImageViewDownloadedCallBack imageCallBack,
				Map<String, Object> callbackParams) {
			this.imageViewReference = new WeakReference<ImageView>(imageView);
			this.imageDownloadedCallBack = imageCallBack;
			this.callbackParams = callbackParams;
		}

		/**
		 * Actual download method.
		 */
		@SuppressWarnings("unchecked")
		@Override
		protected Bitmap doInBackground(Object... params) {
			url = (String) params[0];
			if (params.length > 1 && params[1] != null
					&& params[1] instanceof Map) {
				callbackParams = ((Map<String, Object>) params[1]);
			}
			return downloadBitmap(url);
		}

		/**
		 * Once the image is downloaded, associates it to the imageView
		 */
		@Override
		protected void onPostExecute(Bitmap bitmap) {
			if (isCancelled()) {
				bitmap = null;
			}

			addBitmapToCache(url, bitmap);
			addBitmapToSDCard(url, bitmap);

			if (imageViewReference != null) {
				ImageView imageView = imageViewReference.get();
				BitmapDownloaderTaskForImageView bitmapDownloaderTask = getBitmapDownloaderTask(imageView);
				// Change bitmap only if this process is still associated with
				// it
				// Or if we don't use any bitmap to task association
				// (NO_DOWNLOADED_DRAWABLE mode)
				if ((this == bitmapDownloaderTask) || (mode != Mode.CORRECT)) {
					imageView.setImageBitmap(bitmap);
				}
				if (null != imageDownloadedCallBack) {
					imageDownloadedCallBack.onImageDownloaded(imageView,
							bitmap, callbackParams);
					if (null != callbackParams) {
						callbackParams.clear();
					}
				}
			}
		}
	}

	/**
	 * The actual AsyncTask that will asynchronously download the image.
	 */
	class BitmapDownloaderTask extends AsyncTask<Object, Void, Bitmap> {
		private String url;
		private Map<String, Object> callbackParams;
		private ImageDownloadedCallBack imageDownloadedCallBack;

		public BitmapDownloaderTask(ImageDownloadedCallBack imageCallBack,
				Map<String, Object> callbackParams) {
			this.imageDownloadedCallBack = imageCallBack;
			this.callbackParams = callbackParams;
		}

		/**
		 * Actual download method.
		 */
		@SuppressWarnings("unchecked")
		@Override
		protected Bitmap doInBackground(Object... params) {
			url = (String) params[0];
			if (params.length > 1 && params[1] != null
					&& params[1] instanceof Map) {
				callbackParams = ((Map<String, Object>) params[1]);
			}
			return downloadBitmap(url);
		}

		/**
		 * Once the image is downloaded, associates it to the imageView
		 */
		@Override
		protected void onPostExecute(Bitmap bitmap) {
			if (isCancelled()) {
				bitmap = null;
			}
			if (null != bitmap) {
				addBitmapToCache(url, bitmap);
				addBitmapToSDCard(url, bitmap);
			}
			if (null != imageDownloadedCallBack) {
				imageDownloadedCallBack.onImageDownloaded(bitmap,
						callbackParams);
				if (null != callbackParams) {
					callbackParams.clear();
				}
			}
		}
	}

	/**
	 * A fake Drawable that will be attached to the imageView while the download
	 * is in progress.
	 * 
	 * <p>
	 * Contains a reference to the actual download task, so that a download task
	 * can be stopped if a new binding is required, and makes sure that only the
	 * last started download process can bind its result, independently of the
	 * download finish order.
	 * </p>
	 */
	static class DownloadedDrawable extends ColorDrawable {
		private final WeakReference<BitmapDownloaderTaskForImageView> bitmapDownloaderTaskReference;

		public DownloadedDrawable(
				BitmapDownloaderTaskForImageView bitmapDownloaderTask) {
			super(Color.BLACK);
			bitmapDownloaderTaskReference = new WeakReference<BitmapDownloaderTaskForImageView>(
					bitmapDownloaderTask);
		}

		public BitmapDownloaderTaskForImageView getBitmapDownloaderTask() {
			return bitmapDownloaderTaskReference.get();
		}
	}

	public void setMode(Mode mode) {
		this.mode = mode;
		clearCache();
	}

	/*
	 * Cache-related fields and methods.
	 * 
	 * We use a hard and a soft cache. A soft reference cache is too
	 * aggressively cleared by the Garbage Collector.
	 */

	private static final int HARD_CACHE_CAPACITY = 10;
	private static final int DELAY_BEFORE_PURGE = 10 * 1000; // in milliseconds

	// Hard cache, with a fixed maximum capacity and a life duration
	private final HashMap<String, Bitmap> sHardBitmapCache = new LinkedHashMap<String, Bitmap>(
			HARD_CACHE_CAPACITY / 2, 0.75f, true) {
		@Override
		protected boolean removeEldestEntry(
				LinkedHashMap.Entry<String, Bitmap> eldest) {
			if (size() > HARD_CACHE_CAPACITY) {
				// Entries push-out of hard reference cache are transferred to
				// soft reference cache
				sSoftBitmapCache.put(eldest.getKey(),
						new SoftReference<Bitmap>(eldest.getValue()));
				return true;
			} else
				return false;
		}
	};

	// Soft cache for bitmaps kicked out of hard cache
	private final static ConcurrentHashMap<String, SoftReference<Bitmap>> sSoftBitmapCache = new ConcurrentHashMap<String, SoftReference<Bitmap>>(
			HARD_CACHE_CAPACITY / 2);

	private final Handler purgeHandler = new Handler();

	private final Runnable purger = new Runnable() {
		public void run() {
			clearCache();
		}
	};

	/**
	 * Adds this bitmap to the cache.
	 * 
	 * @param bitmap
	 *            The newly downloaded bitmap.
	 */
	private void addBitmapToCache(String url, Bitmap bitmap) {
		if (bitmap != null) {
			synchronized (sHardBitmapCache) {
				sHardBitmapCache.put(url, bitmap);
			}
		}
	}

	/**
	 * @param url
	 *            The URL of the image that will be retrieved from the cache.
	 * @return The cached bitmap or null if it was not found.
	 */
	private Bitmap getBitmapFromCache(String url) {
		// First try the hard reference cache
		synchronized (sHardBitmapCache) {
			final Bitmap bitmap = sHardBitmapCache.get(url);
			if (bitmap != null) {
				// Bitmap found in hard cache
				// Move element to first position, so that it is removed last
				sHardBitmapCache.remove(url);
				sHardBitmapCache.put(url, bitmap);
				return bitmap;
			}
		}

		// Then try the soft reference cache
		SoftReference<Bitmap> bitmapReference = sSoftBitmapCache.get(url);
		if (bitmapReference != null) {
			final Bitmap bitmap = bitmapReference.get();
			if (bitmap != null) {
				// Bitmap found in soft cache
				return bitmap;
			} else {
				// Soft reference has been Garbage Collected
				sSoftBitmapCache.remove(url);
			}
		}

		return null;
	}

	/**
	 * Clears the image cache used internally to improve performance. Note that
	 * for memory efficiency reasons, the cache will automatically be cleared
	 * after a certain inactivity delay.
	 */
	public void clearCache() {
		sHardBitmapCache.clear();
		sSoftBitmapCache.clear();
	}

	/**
	 * Allow a new delay before the automatic cache clear is done.
	 */
	private void resetPurgeTimer() {
		purgeHandler.removeCallbacks(purger);
		purgeHandler.postDelayed(purger, DELAY_BEFORE_PURGE);
	}

	public interface ImageViewDownloadedCallBack {
		public void onImageDownloaded(ImageView imageView, Bitmap bitmap,
				Map<String, Object> callbackParams);
	}

	public interface ImageDownloadedCallBack {
		public void onImageDownloaded(Bitmap bitmap,
				Map<String, Object> callbackParams);
	}

	private Bitmap getBitmapFromSDCard(String url) {
		String bitmapName = url.substring(url.lastIndexOf("/") + 1);
		if (Environment.getExternalStorageState().equals(
				Environment.MEDIA_MOUNTED)) {
			/**
			 * if the bitmap in sdcard
			 */
			File cacheBitmapFile = new File(Constants.SD_CARD_IMAGE_CACHE_FOLD
					+ bitmapName);
			if (cacheBitmapFile.exists()) {
				return BitmapFactory.decodeFile(cacheBitmapFile.getPath());
			}
		}
		return null;
	}

	private void addBitmapToSDCard(String url, Bitmap bitmap) {
		if (Environment.getExternalStorageState().equals(
				Environment.MEDIA_MOUNTED)
				&& bitmap != null) {
			String bitmapName = url.substring(url.lastIndexOf("/") + 1);
			saveBitmapToSDCard(bitmap, Constants.SD_CARD_IMAGE_CACHE_FOLD
					+ bitmapName);
		}
	}

	private void saveBitmapToSDCard(Bitmap bitmap, String filePath) {
		File dirctory = new File(Constants.SD_CARD_IMAGE_CACHE_FOLD);
		try {
			if (!dirctory.exists() || !dirctory.isDirectory()) {
				dirctory.mkdirs();
			}
			File f = new File(filePath);
			f.createNewFile();
			FileOutputStream fOut = null;
			fOut = new FileOutputStream(f);
			if (filePath.endsWith("png")) {
				bitmap.compress(Bitmap.CompressFormat.PNG, 100, fOut);
			} else {
				bitmap.compress(Bitmap.CompressFormat.JPEG, 100, fOut);
			}
			fOut.flush();
			fOut.close();
		} catch (FileNotFoundException e) {
			Log.w("ImageDownloader", "Error while save bitmap to sdcard "
					+ filePath);
		} catch (IOException e) {
			Log.w("ImageDownloader", "Error while save bitmap to sdcard "
					+ filePath);
		}
	}

}